In my prior U.S. Pat. Nos. 3,870,350 and 4,740,024 there are described tong-type clamps which have a variety of uses. These clamps include a pair of clamping members which are pivotally connected to one another intermediate their ends. The portions of the clamping members extending in one direction from the pivot connection serve as handles for the clamp and the portions of the members extending in the other direction from the pivot connection serve as the clamping arms.
The clamping arms terminate in facing clamping jaws which are adapted to grip a workpiece therebetween. As the handles are moved toward one another the clamping arms correspondingly move together.
A locking cam is carried by one of the clamping members. The cam is pivotally attached to the clamping member and is adapted to be rotated in a manner such that its peripheral surface engages one of the handle members to prevent the clamp from opening when the clamp is connected to a workpiece. When the cam member is rotated in the opposite direction, the peripheral surface is moved away from the handle and allows the clamp to be opened to release the clamp from the workpiece.
One problem with the foregoing types of clamps is that the clamping jaws are limited in the extent to which they can be opened. Because the cam member is carried on one of the clamping members, it limits the extent to which the handle members can be moved apart. As a result, there is an inherent limitation in such types of clamps regarding the width of the opening between the clamping jaws when the clamp is fully opened. Consequently, such types of clamps are limited in terms of the size of workpieces onto which they can be positioned.
There has not heretofore been provided a tong-type clamp with locking cam which can be opened to any desired extent.